For a long time I have wondered why it is that some of the warmer regions of the world yield up such involved cuisines. Why, on a sweltering afternoon in Louisiana or in Bangkok would one choose to undertake the long, steamy process of producing jambalaya or handmade curried noodles, rather than fleeing to the shade of the nearest tree? Charles Phan, whose Slanted Door restaurant has won acclaim in the Bay Area, made me ask these questions. In his heartfelt cookbook, “Vietnamese Home Cooking,” none of the recipes looked particularly difficult. But there was always just one more step — a peanut sauce, a marinade, a garnish, a dip — than I honestly felt like attempting.